Here's why:

* Saturated rock: This means the rock is filled with water.

* Below the soil: The water table is the boundary between the zone of saturation (where the rock is filled with water) and the zone of aeration (where the rock is mostly air).

* Mark rim: This could refer to the level of the water table itself, as it can sometimes rise and fall depending on rainfall and other factors.

In summary: The water table is the upper level of the saturated zone in the ground, and it's often marked by the presence of water in wells or springs.